Parse actions skipped inside delimited_list #345
Description
Hello,
I'm not sure if this is a bona-fide bug, or if I'm misusing pyparsing :-)
I have a huge pyparsing grammar for ASN.1 syntax over in https://github.com/kimgr/asn1ate/blob/master/asn1ate/parser.py. The repro below is not minimal. but uses some techniques from asn1ate's parser to demonstrate what I'm trying to do:
#!/usr/bin/env python
from pyparsing import *
class AnnotatedToken(object):
def __init__(self, kind, elements):
self.kind = kind
self.elements = elements
def __str__(self):
return 'T(%s, %r)' % (self.kind, self.elements)
__repr__ = __str__
def grammar():
def annotate(name):
def _(t):
return AnnotatedToken(name, t.asList())
return _
identifier = Word(srange('[a-z0-9]'))
numeral = Word(nums)
named_number_value = Suppress('(') + numeral + Suppress(')')
named_number = identifier + named_number_value
named_number_list = (Suppress('{') +
Group(Optional(delimitedList(named_number))) +
Suppress('}'))
identifier.setParseAction(annotate("id"))
named_number.setParseAction(annotate("nn"))
# BUG(?): This parse action is never called after commit
# 9987004c94ccf7d9b6b3adbcf06d05d2ff197737
named_number_value.setParseAction(annotate("val"))
g = OneOrMore(named_number_list)
return g
g = grammar()
res = g.parseString("""
{ x1(1), x2(2) }
""")
print(res.dump())
The concrete problem I'm seeing downstream is that a parse action intended to decorate the parse result with a type name is never called, and so later stages can't use the annotation to identify what kind of element it is.
I think the issue is that delimited_list now mutates the expression by calling its streamline method: 9987004#diff-daba53cec7bed1be7b180ee5e8378c772408d07afe6f2cad6d62e966993b9e45L38.
I haven't fully gotten my head around what streamline is supposed to do, but it seems to reduce the result to a literal value, skipping over any interim rules and parse actions.
Is that a bug? Or is there a way to phrase the grammar in a way that it works with both old and new pyparsing?
Thanks!